1. Field of the Invention
The present invention relates generally to the field of molecular biology. More specifically, the invention relates to plant genes involved in plant morphology and methods of use thereof.
2. Description of the Related Art
There is a great need in the art for new genes capable of improving biomass, for example by altering leaf morphology. As the primary photosynthetic organs and sites of gaseous exchange, leaves play a crucial role for the success of land plants. Wider leaf area allows more efficient capture of solar energy and, together with thin and flat surfaces, promotes efficient gaseous exchange (Tsukaya, 2005). Although broader leaves are more efficient in terms of photosynthesis, they are not equally preferable for all environments, as this feature also exposes them to lose more water by transpiration in warm and dry areas. Plants adapted to the arid tropics, such as cactus for example, employ small and thick leaves, or perform photosynthesis in their stems, and have spines instead of leaves, to cope with the problem of dehydration. As a consequence, they grow slowly because their capacity for photosynthesis is limited by the available surface area.
Other plants, which grow mainly in tropical and subtropical environments, such as sugarcane, maize and sorghum, modify their leaves with characteristic Krantz anatomy for C4 photosynthesis. In this case, the leaves contain two interconnected but distinct cell types in which the thin-walled mesophyll cells close to the surface facilitate CO2 entry whereas the thick-walled bundle sheath cells beneath the mesophyll serve as the actual sites of photosynthesis where water loss is relatively reduced. When the same species is grown under different conditions, for example, in both sun and shade, leaf morphology or arrangement of cells varies between plants grown in different environments. Leaves, therefore, maintain a wide range of plasticity in size and shape, and have adaptive significance for plants to successfully colonize a particular environment. However, little is known about the genetic determinants leaf shape and size. A gene affecting leaf shape or size could be useful for increasing biomass. The present invention provides such a gene.